The present invention relates to fuel systems for supplying gas, for example methane, LPG or hydrogen, to vehicle engines. In particular, the invention relates to fuel systems for supplying gas, of the type comprising:
at least one tank, in which gas under high pressure is accumulated;
a manifold for distribution of the gas, which has an inlet connected to the tank and a plurality of outlets connected to the respective delivery devices;
a pressure-reducer device, set in the connection between the tank and the manifold;
one or more valves set at the outlet of the gas from one or more tanks and in a position corresponding to the pressure-reducer device;
first and second sensor means for detecting respectively: pressure of the gas upstream of the pressure-reducer device, i.e., in the high-pressure part of the system, and pressure and temperature of the gas downstream of the pressure-reducer device, i.e., in the low-pressure part of the system; and
electronic control means capable of regulating the rate of gas flow in the fuel system.
Gas-supply systems of the type referred to above have been known for some time. A system of this type is, for instance, described and illustrated in the European patent No. EPO 801 223 in the name of the present applicant.
The purpose of the present invention is that of providing a diagnostics system for tracing leaks from a fuel system of the type referred to above and for checking proper operation of the valves of the system.
With a view to achieving the above purpose, the subject of the invention is a gas-supply system of the type referred to above, which is further characterized in that the aforesaid electronic control means are designed for receiving the signals from said first and second sensor means and are programmed for:
processing the data regarding the low-pressure part of the system, which come from said first sensor means, according to a predetermined algorithm, at predefined instants, in order to enable timely detection of incorrect functioning of said second valve or a possible gas leak from the low-pressure part of the system; and
processing the data regarding the high-pressure part of the system, which come from said second sensor means, according to a predetermined algorithm, during the step of gas delivery in order to enable timely detection of incorrect functioning of any possible valves referred to previously or a possible gas leak from the high-pressure part of the system.
Of course, the basic idea underlying the present invention already lies in the very problem that the invention solves. Up to the present day, in fact, no systems of any kind capable of performing diagnostics operations of the type referred to above have been proposed. Consequently, even before being identified in the use of a specific algorithm in order to achieve the pre-set purpose, the invention is to be identified in having posed itself the problem of creating a diagnostics system in a gas-supply system of the type specified above.
In the preferred embodiment of the invention, the aforesaid electronic control means are programmed for carrying out a check on the low-pressure part of the system in a first step immediately after the command for cessation of gas delivery, but prior to the actual cessation thereof, in order to enable detection of any possible malfunctioning of the second valve, and in a second step, following upon said cessation of operation, in order to enable detection of any possible gas leaks.
Again in the case of the preferred embodiment of the invention, the aforesaid electronic control means are programmed for carrying out a check on the high-pressure part of the system in a first step, when a condition of minimum delivery is reached for the first time immediately after filling of the gas tank, in order to enable detection of any possible gas leaks, and in a second step, at the first reactivation of the system after filling of the gas tank, in order to enable detection of any possible malfunctioning of the first valves.